(a) Field of the Invention
The present invention relates to an air cushion manufacturing machine, and more particularly to an air cushion manufacturing machine that carries out a punctuate periodic micro heating process to a heat sealer based on a circular sealing course, such that the heat sealer can achieve a constant heat compensation for each sealing course.
(b) Description of the Related Art
To overcome the problems of conventional packaging materials with a poor cushion effect or a serious pollution issue, manufacturers have developed an air cushion that seals air between two layers of films to form successive air columns, and thus the air cushion is a double-layer film with a side as a seal side and the other side as an open side, and the air cushion is manufactured by a manufacturing procedure comprising the steps of: circular intermittent air inflation→thermal sealing→feed.
The conventional sealing machines are mainly classified into two types: a direct heating type and an instant heating type, wherein the direct heating type sealing machine is applicable for a thicker material only and such sealing machine is coupled to a power supply and heated continuously, and thus wasting tremendous electric power. Therefore, most of the conventional air cushion manufacturing machines adopt the instant heat sealing method. However, the heat sealing method has the following drawbacks in the manufacture of the air cushion. In FIGS. 1 and 2, the power supply a supplies electric energy required by an electrothermal wire of the sealing device b and converts the electric energy into heat energy, and the sealing device b is coupled to a temperature sensor c, such that when the film is sealed, the temperature sensor c feeds a detected temperature signal back to the power supply a, but such signal feedback d usually causes a delay or an inaccuracy. The instant high temperature desired for sealing films will be advanced or delayed by a period, so that the electrothermal wire is not at the best heating temperature at the moment of sealing the films, and a low yield rate of sealing is resulted. Furthermore, the way of resupplying electric power to compensate the electrothermal wire after the electrothermal wire goes through the instant high temperature and cooling process may break or crack the electrothermal wire easily, and the lifespan may be reduced.
Obviously, the conventional air cushion manufacturing machine requires further improvements.